Evolutionary Pathways of Historic Urban Landscapes: Spatial Persistence and Functional Adaptation in Two Chinese Historic Districts

Historic districts result from the long-term interaction of spatial persistence and functional change. Previous studies have examined historical development and historic layering, but less attention has focused on connections between historical formation and present-day spatial conditions, particularly how historically formed spaces persist and adapt to changing urban needs through functional adjustment. From the dynamic perspective of the Historic Urban Landscape (HUL), this study develops a Formation–Persistence–Adaptation (FPA) framework and applies it to Yihe Road in Nanjing and Sinan Road in Shanghai. This study integrates historical maps, remote sensing imagery, planning archives, and spatial data, combined with analyses of building formation contribution, building retention, functional mix, and spatial functional transition. The analysis identifies two contrasting evolutionary patterns. Yihe Road exhibits “concentrated formation–high spatial persistence–functional persistence–incremental adaptation,” whereas Sinan Road exhibits “incremental formation–layered spatial persistence–functional restructuring–adaptive reuse.” The findings demonstrate that physical persistence and functional adaptation can coexist in historic districts, with their relationships taking different forms across the evolutionary pathways. The FPA framework links observable historic layering to its processes of formation, persistence, and continued use, providing a process-based perspective for understanding HUL evolution and informing differentiated conservation strategies.